SOC estimation method and system of energy storage battery

Abstract

The invention discloses an SOC estimation method and system for an energy storage battery, and the method comprises the steps: collecting a working current and a low-power-consumption current through a double-current sampling loop, carrying out the smooth switching to obtain fusion current data, calibrating an initial SOC value based on a standby open-circuit voltage during standing, carrying out the ampere-hour integration through the combination of the fusion current and a corresponding integration coefficient, and obtaining a preliminary SOC estimation value, and processing the voltage data through temperature and current compensation, obtaining a reference SOC value to correct the initial SOC, and finally carrying out end calibration or direct output on the SOC according to whether the single voltage enters a charging and discharging end period interval, thereby realizing accurate estimation. According to the invention, the accuracy of SOC estimation can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method and system for estimating the state of charge (SOC) of an energy storage battery. Background Technology

[0002] In the field of energy storage batteries, especially in energy storage applications such as home and commercial energy storage, accurate estimation of the battery's state of charge (SOC) is crucial for battery safety, range reliability, and lifespan. Current mainstream SOC estimation methods typically only configure one current sampling loop. This loop needs to cover a wide range of sampling requirements, from low-power small currents (such as microampere-level currents during standby of energy storage systems) to high-power operating currents (such as hundred-ampere-level currents during kilowatt-level charging and discharging). By combining the collected current data with a preset fixed integration coefficient, the remaining battery capacity is calculated using the ampere-hour integration method, and then the estimated SOC value is obtained.

[0003] The existing technology has the following problems: when the single-loop current sampling covers a wide current range, it is easy to cause inaccurate current sampling with low power consumption, which in turn causes deviation in SOC calculation. Furthermore, under environmental factors such as low temperature, the SOC jump is prone to occur when the battery is undervoltage protection, which cannot accurately reflect the actual usable power of the battery. Summary of the Invention

[0004] This invention provides a method and system for estimating the State of Charge (SOC) of an energy storage battery, which can effectively improve the accuracy of SOC estimation.

[0005] An embodiment of the present invention provides a method for estimating the state of charge (SOC) of an energy storage battery, comprising: The working current and low-power current of the energy storage battery are collected by the working current sampling circuit and the low-power current sampling circuit respectively, and the two currents are smoothly switched to obtain fused current data. Under the condition that the resting time exceeds a set threshold, the standby open-circuit voltage of the energy storage battery is obtained, and the SOC is calibrated once based on the standby open-circuit voltage to obtain the calibration start SOC value. Based on the fused current data and the integral coefficient corresponding to the calibration initial SOC value, an ampere-hour integral calculation is performed to obtain a preliminary SOC estimate. The voltage data of the energy storage battery is collected, and temperature compensation and current compensation are performed on the voltage data to obtain the compensation voltage; A reference SOC value is obtained based on the compensation voltage. The reference SOC value is compared with the preliminary SOC estimate to determine the correction direction and correction amount. The preliminary SOC estimate is then corrected to obtain the SOC value to be calibrated. If the voltage of a single cell of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate.

[0006] As an improvement to the above scheme, the step of acquiring the working current and low-power current of the energy storage battery through the working current sampling circuit and the low-power current sampling circuit respectively, and performing smooth switching processing on the two currents to obtain fused current data includes the following sub-steps: The operating current of the energy storage battery is collected by the operating current sampling circuit to obtain the operating current data; The low-power current of the energy storage battery is collected by a low-power current sampling circuit to obtain low-power current data. The amplitude of the operating current data is compared with that of the low power consumption current data to obtain the amplitude comparison result; Based on the amplitude comparison results, the operating current data and the low-power current data are subjected to a weighted smoothing switching operation according to the set switching threshold range to obtain the fused current data.

[0007] As an improvement to the above scheme, the step of obtaining the standby open-circuit voltage of the energy storage battery under the condition that the resting time exceeds a set threshold, and calibrating the SOC based on the standby open-circuit voltage to obtain the calibration starting SOC value, includes the following sub-steps: The set threshold is determined by the RTC time difference, and the result of the settling time determination is obtained. When the static judgment result is yes, the average voltage of the energy storage battery is collected as the standby open circuit voltage; The standby open-circuit voltage is linearly interpolated with the SOC mapping table to obtain the calibration starting SOC value.

[0008] As an improvement to the above scheme, the step of performing ampere-hour integration calculation based on the fused current data and the integration coefficient corresponding to the calibration initial SOC value to obtain a preliminary SOC estimate includes the following sub-steps: The cumulative energy value is obtained by integrating the fused current data over the time period; The integral coefficients are obtained by querying the integral coefficient mapping table based on the initial SOC value of the calibration. Multiply the cumulative power consumption value by the integral coefficient to obtain the weighted power consumption value; Add the initial SOC value to the weighted energy value to obtain a preliminary SOC estimate.

[0009] As an improvement to the above solution, the step of collecting the voltage data of the energy storage battery, performing temperature compensation and current compensation on the voltage data to obtain the compensated voltage includes the following sub-steps: The temperature data of the energy storage battery is collected, and the voltage data is temperature compensated according to the temperature compensation coefficient to obtain the temperature compensated voltage. The fusion current data is collected, and the temperature compensation voltage is compensated for based on the current compensation coefficient to obtain the compensation voltage.

[0010] As an improvement to the above scheme, the step of obtaining a reference SOC value based on the compensation voltage, comparing the reference SOC value with the preliminary SOC estimate to determine the correction direction and amount, and correcting the preliminary SOC estimate to obtain the SOC value to be calibrated includes the following sub-steps: The compensation voltage is linearly interpolated with the SOC mapping table to obtain the reference SOC value. The difference between the reference SOC value and the preliminary SOC estimate is calculated to obtain the SOC difference. The correction direction and correction amount are determined based on the SOC difference. The correction amount is added to the initial SOC estimate to obtain the SOC value to be calibrated.

[0011] As an improvement to the above scheme, if the voltage of a single cell of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate. This includes the following sub-steps: Determine whether the individual cell voltage is within the set voltage range at the end of charging or the set voltage range at the end of discharging to obtain the final judgment result; When the final judgment result is yes, the final correction amount is calculated based on the linear relationship between the unit voltage and the SOC. The end correction is added to the SOC value to be calibrated to obtain the final SOC estimate; If the final determination result is negative, the SOC value to be calibrated will be directly used as the final SOC estimate.

[0012] Another embodiment of the present invention provides a SOC estimation system for an energy storage battery, comprising: Low-power current acquisition circuit, used to acquire the low-power current of energy storage battery; A working current sampling circuit is used to collect the working current of the energy storage battery; and, The processor, connected to both the low-power current acquisition circuit and the operating current sampling circuit, is used for: The operating current and the low-power current are acquired, and the two currents are smoothly switched to obtain fused current data. Under the condition that the resting time exceeds a set threshold, the standby open-circuit voltage of the energy storage battery is obtained, and the SOC is calibrated once based on the standby open-circuit voltage to obtain the calibration start SOC value. Based on the fused current data and the integral coefficient corresponding to the calibration initial SOC value, an ampere-hour integral calculation is performed to obtain a preliminary SOC estimate. The voltage data of the energy storage battery is collected, and temperature compensation and current compensation are performed on the voltage data to obtain the compensation voltage; A reference SOC value is obtained based on the compensation voltage. The reference SOC value is compared with the preliminary SOC estimate to determine the correction direction and correction amount. The preliminary SOC estimate is then corrected to obtain the SOC value to be calibrated. If the voltage of a single cell of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate.

[0013] As an improvement to the above solution, the processor is used to collect the operating current and low-power current of the energy storage battery through the operating current sampling circuit and the low-power current sampling circuit respectively, and to perform smooth switching processing on the two currents to obtain fused current data. Specifically, it is used for: The operating current of the energy storage battery is collected by the operating current sampling circuit to obtain the operating current data; The low-power current of the energy storage battery is collected by a low-power current sampling circuit to obtain low-power current data. The amplitude of the operating current data is compared with that of the low power consumption current data to obtain the amplitude comparison result; Based on the amplitude comparison results, the operating current data and the low-power current data are subjected to a weighted smoothing switching operation according to the set switching threshold range to obtain the fused current data.

[0014] As an improvement to the above solution, when the processor acquires the standby open-circuit voltage of the energy storage battery under the condition that the resting time exceeds a set threshold, and performs a calibration of the SOC based on the standby open-circuit voltage to obtain the calibration starting SOC value, it is specifically used for: The set threshold is determined by the RTC time difference, and the result of the settling time determination is obtained. When the static judgment result is yes, the average voltage of the energy storage battery is collected as the standby open circuit voltage; The standby open-circuit voltage is linearly interpolated with the SOC mapping table to obtain the calibration starting SOC value.

[0015] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: By employing a dual-channel sampling system ("operating current sampling circuit + low-power current sampling circuit") with smooth switching, a wide-range, high-precision fused current data is first obtained. Only when the resting time exceeds a set threshold is the standby open-circuit voltage used for a one-time calibration to obtain the initial SOC value. Subsequently, the fused current data is integrated with the integral coefficient corresponding to this initial SOC value to obtain a preliminary SOC estimate. Then, the SOC value is obtained by querying the SOC mapping table using the compensation voltage after temperature and current compensation. After comparing it with the preliminary SOC estimate, the correction direction and amount are determined and corrected to obtain the SOC value to be calibrated. Finally, when the individual cell voltage enters the set voltage range at the end of the charge / discharge period, end calibration is performed based on the voltage characteristics. Otherwise, the SOC value to be calibrated is directly output as the final SOC estimate. This approach improves the accuracy of low current through dual-channel sampling, eliminates accumulated errors through one-time calibration with standby OCV, and suppresses SOC jumps through real-time compensation and end calibration. As can be seen from the above analysis, the embodiments of the present invention effectively solve the problems of low power consumption, inaccurate current sampling, and SOC jump during battery undervoltage protection in the prior art caused by only single-loop current sampling. It realizes accurate estimation of SOC of energy storage battery and ensures smooth SOC change, accurately reflects the actual usable power of battery, and thus effectively improves the accuracy of SOC estimation. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a method for estimating the SOC of an energy storage battery according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a SOC estimation system for an energy storage battery according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a working current acquisition circuit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a low-power current acquisition circuit provided in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the variation of OCV with SOC and temperature according to an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] See Figure 1 This is a flowchart illustrating a method for estimating the State of Charge (SOC) of an energy storage battery according to an embodiment of the present invention. The method for estimating the SOC of the energy storage battery includes: S10: The working current and low power consumption current of the energy storage battery are collected by the working current sampling circuit and the low power consumption current sampling circuit respectively, and the two currents are smoothly switched to obtain fused current data. S11, under the condition that the resting time exceeds the set threshold, the standby open circuit voltage of the energy storage battery is obtained, and the SOC is calibrated once according to the standby open circuit voltage to obtain the calibration start SOC value. S12, perform ampere-hour integration calculation based on the fused current data and the integration coefficient corresponding to the calibration start SOC value to obtain a preliminary SOC estimate; S13, Collect the voltage data of the energy storage battery, perform temperature compensation and current compensation on the voltage data to obtain the compensation voltage; S14. Obtain a reference SOC value based on the compensation voltage, compare the reference SOC value with the preliminary SOC estimate to determine the correction direction and correction amount, and correct the preliminary SOC estimate to obtain the SOC value to be calibrated. S15, if the single cell voltage of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate.

[0019] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: By employing a dual-channel sampling system ("operating current sampling circuit + low-power current sampling circuit") with smooth switching, a wide-range, high-precision fused current data is first obtained. Only when the resting time exceeds a set threshold is the standby open-circuit voltage used for a one-time calibration to obtain the initial SOC value. Subsequently, the fused current data is integrated with the integral coefficient corresponding to this initial SOC value to obtain a preliminary SOC estimate. Then, the SOC value is obtained by querying the SOC mapping table using the compensation voltage after temperature and current compensation. After comparing it with the preliminary SOC estimate, the correction direction and amount are determined and corrected to obtain the SOC value to be calibrated. Finally, when the individual cell voltage enters the set voltage range at the end of the charge / discharge period, end calibration is performed based on the voltage characteristics. Otherwise, the SOC value to be calibrated is directly output as the final SOC estimate. This approach improves the accuracy of low current through dual-channel sampling, eliminates accumulated errors through one-time calibration with standby OCV, and suppresses SOC jumps through real-time compensation and end calibration. As can be seen from the above analysis, the embodiments of the present invention effectively solve the problems of low power consumption, inaccurate current sampling, and SOC jump during battery undervoltage protection in the prior art caused by only single-loop current sampling. It realizes accurate estimation of SOC of energy storage battery and ensures smooth SOC change, accurately reflects the actual usable power of battery, and thus effectively improves the accuracy of SOC estimation.

[0020] As an example of the above scheme, the step of acquiring the working current and low-power current of the energy storage battery through the working current sampling circuit and the low-power current sampling circuit respectively, and performing smooth switching processing on the two currents to obtain fused current data includes the following sub-steps: The operating current of the energy storage battery is collected by the operating current sampling circuit to obtain the operating current data; The low-power current of the energy storage battery is collected by a low-power current sampling circuit to obtain low-power current data. The amplitude of the operating current data is compared with that of the low power consumption current data to obtain the amplitude comparison result; Based on the amplitude comparison results, the operating current data and the low-power current data are subjected to a weighted smoothing switching operation according to the set switching threshold range to obtain the fused current data.

[0021] In this embodiment, addressing the deficiency in existing technologies where a single current sampling loop, due to its wide current coverage, results in insufficient accuracy for small current sampling, a collaborative design of "dual-loop independent sampling + amplitude judgment + weighted smooth switching" is adopted. This involves separately acquiring current signals of different amplitudes through a working current sampling circuit and a low-power current sampling circuit, avoiding accuracy loss when a single loop handles both large and small currents. Furthermore, amplitude comparison clarifies the current operating condition, and weighted calculations are performed on the two data streams based on a set switching threshold range, achieving smooth switching without abrupt changes. The final output is fused current data adapted to all current operating conditions. This embodiment eliminates signal abrupt interference during the switching of the two sampling data streams through smooth switching, ensuring the stability of the current data and thus improving the overall accuracy of SOC estimation.

[0022] Specifically, the working process of this embodiment is as follows: 1. A working current sampling circuit (adapted for high-current acquisition scenarios, such as the 0-100A discharge current acquisition circuit mentioned in the document, including sampling resistors, TP5534 amplifier chip, and other hardware components) is used to collect the working current of the energy storage battery during charging and discharging (such as the 100A-level current during kilowatt-level charging and discharging). Through circuit signal conversion and filtering, working current data that accurately reflects the actual working current magnitude is obtained, ensuring the range and accuracy of data acquisition under high-current conditions are well-suited. See also... Figure 3 This operating current sampling circuit is a differential input active filter amplification structure. In the circuit connection, the input voltages Vi1 and Vi2 are first introduced through a path formed by Rs and R, which, together with the grounding resistor R1, forms a differential input mode. The non-inverting input of the operational amplifier is connected to the preceding resistor node through capacitor C1, and the inverting input is connected to the output Vout1 through a feedback network composed of C2 and R1. During operation, the differential input suppresses common-mode noise. Initial filtering is achieved through an RC network composed of R and C1, followed by signal amplification and further filtering and conditioning using the operational amplifier and the feedback network C2 and R1. Finally, the output Vout1 processes the input current-related voltage signal, providing an accurate and low-noise voltage signal for subsequent acquisition of operating current data.

[0023] 2. Utilizing an independent low-power, low-current sampling circuit (adapted to low-current acquisition scenarios, employing low-resistance sampling resistors and high-sensitivity signal conditioning circuits), the system acquires the low-power current (e.g., microampere to milliampere level) of the energy storage battery during standby and low-power operation. After signal amplification and noise reduction, the system obtains low-power, low-current data with accuracy meeting the requirements of low-current operating conditions, avoiding the masking of low-current signals by inherent errors in high-current sampling circuits. See [reference needed]. Figure 4The low-power current sampling circuit is a two-stage cascaded active filter amplifier circuit. In the first stage, the input voltages Vi1 and Vi2 are connected via Rs and R, forming a differential input with the grounding resistor R1. The non-inverting input of the operational amplifier is connected to C1 and the preceding resistor, while the inverting input is grounded via R1. C2 and R1 form a feedback network, and the output Vout1 is then transmitted to the second stage via R. In the second stage, the non-inverting input of the operational amplifier is connected to C1 and the preceding resistor, while the inverting input is grounded via R2. C2 and R2 form a feedback network, ultimately outputting Vout. During operation, the two-stage RC network and operational amplifier feedback first suppress common-mode noise and perform preliminary filtering and amplification on the differential inputs Vi1 and Vi2 to obtain Vout1. Then, the second stage enhances filtering and adjusts the characteristics to output a low-noise, stable signal. This can convert the small current into a suitable voltage for accurate acquisition of low-power current.

[0024] 3. The data processing module is invoked to convert the collected operating current data and low-power current data into amplitude parameters of a unified dimension (such as the effective value of the current). The amplitudes of the two are compared through a preset numerical comparison logic. At the same time, combined with the switching threshold range set in this patent (such as dividing the range with 1A as the low current threshold and 100A as the high current threshold), the current dominant current type is determined, and amplitude comparison results such as "operating current amplitude ≥ threshold" and "low-power current amplitude < threshold" are obtained, providing a basis for subsequent switching decisions.

[0025] 4. Based on the amplitude comparison results, a preset weighted smoothing switching algorithm is activated. If the operating current amplitude is within the high current threshold range, the operating current data is assigned a higher weight (e.g., weight coefficient 0.9), and the low-power current data is assigned a lower weight (e.g., weight coefficient 0.1). If the low-power current amplitude is within the low current threshold range, the weights are reassigned in the opposite direction. If the current amplitude is within the threshold transition range, the weights are dynamically adjusted proportionally. The smooth transition between the two data streams is achieved through the calculation "fused current data = operating current data × operating current weight + low-power current data × low-power current weight," ultimately outputting high-precision fused current data without abrupt changes. This provides reliable input for subsequent SOC estimation based on the ampere-hour integration method (formula: SOC = SOC0 + Ki × ∫Ii × ΔT, where Ii is the fused current data output in this step).

[0026] As an example of the above scheme, the step of obtaining the standby open-circuit voltage of the energy storage battery under the condition that the resting time exceeds a set threshold, and calibrating the SOC based on the standby open-circuit voltage to obtain the calibration starting SOC value, includes the following sub-steps: The set threshold is determined by the RTC time difference, and the result of the settling time determination is obtained. When the static judgment result is yes, the average voltage of the energy storage battery is collected as the standby open circuit voltage; The standby open-circuit voltage is linearly interpolated with the SOC mapping table to obtain the calibration starting SOC value.

[0027] In this embodiment, addressing the problem in existing technologies where the initial SOC value is easily affected by accumulated errors and fails to reflect the true state of the battery, the "open-circuit voltage (OCV) in the resting state" is used as the core calibration basis. A one-time SOC calibration is achieved through "time judgment - voltage acquisition - mapping interpolation": First, the RTC time difference is used to accurately determine whether the battery has met sufficient resting time (ensuring voltage stability and meeting OCV acquisition conditions). Then, a stable average voltage is acquired as the standby open-circuit voltage. Finally, the mapping relationship between OCV and SOC is combined with linear interpolation to improve calibration accuracy, obtaining a reliable initial SOC value. Therefore, this embodiment solves the SOC calibration deviation problem caused by voltage instability in non-resting states, providing a high-precision initial benchmark for subsequent SOC estimation based on the ampere-hour integration method, reducing accumulated integration errors from the source. Simultaneously, linear interpolation further improves the accuracy of OCV to SOC conversion, ensuring that the initial SOC value accurately reflects the actual state of charge of the battery.

[0028] Specifically, the working process of this embodiment is as follows: The Real-Time Clock (RTC) module in the Battery Management System (BMS) is invoked to record the start time of the battery from the end of its last charge / discharge cycle (or the switch from a non-static state to a static state). The time difference between the current time and the start time is calculated using the RTC. This time difference is compared with a preset static time threshold (such as 30 minutes mentioned in the document). If the time difference is ≥ the set threshold, the static judgment result is "yes" (OCV acquisition conditions are met). If the time difference is < the set threshold, the static judgment result is "no" (time difference monitoring continues). This method accurately determines whether the battery is in a stable static state.

[0029] When the static judgment result is "yes", the battery voltage acquisition module is activated to sample the individual cell voltage of the energy storage battery multiple times (e.g., 10 consecutive times). After removing abnormal fluctuation data (e.g., extreme values ​​that exceed the normal voltage range), the average voltage is calculated using the formula "average voltage = (sum of multiple effective individual cell voltage samples) / number of samples". This average voltage is used as the standby open circuit voltage (OCV) to ensure that the acquired voltage value can reflect the true voltage characteristics of the battery under stable open circuit conditions.

[0030] The system calls a preset standby open-circuit voltage and SOC mapping table (OCV-SOC mapping table, which contains multiple sets of "OCV value-SOC value" corresponding data, such as SOC=50% when OCV=3.3V and SOC=60% when OCV=3.4V). If the collected standby open-circuit voltage happens to match a certain OCV value in the mapping table, the corresponding SOC value is directly obtained. If the standby open-circuit voltage is between two adjacent OCV values ​​in the mapping table (set as OCV1 and OCV2, with corresponding SOC values ​​of SOC1 and SOC2, and OCV1 < standby open-circuit voltage < OCV2), the calibration starting SOC value is calculated by the linear interpolation formula "SOC=SOC1+(standby open-circuit voltage-OCV1)×(SOC2-SOC1) / (OCV2-OCV1)", realizing the accurate conversion of OCV to SOC, and finally outputting the calibration starting SOC value as the initial reference for SOC estimation.

[0031] As an improvement to the above scheme, the step of performing ampere-hour integration calculation based on the fused current data and the integration coefficient corresponding to the calibration initial SOC value to obtain a preliminary SOC estimate includes the following sub-steps: The cumulative energy value is obtained by integrating the fused current data over the time period; The integral coefficients are obtained by querying the integral coefficient mapping table based on the initial SOC value of the calibration. Multiply the cumulative power consumption value by the integral coefficient to obtain the weighted power consumption value; Add the initial SOC value to the weighted energy value to obtain a preliminary SOC estimate.

[0032] In this embodiment, addressing the issue that traditional ampere-hour integration methods, which use fixed integration coefficients, are prone to accumulating estimation errors due to current acquisition deviations and changes in battery state, this embodiment first integrates precise fused current data over time to obtain a cumulative charge value reflecting the actual change in battery capacity. Then, it matches integration coefficients adapted to the current battery state based on the initial calibration SOC value, avoiding the limitations of fixed coefficients. Finally, it superimposes the weighted calculation with the initial SOC value to obtain a preliminary SOC estimate. Therefore, this embodiment provides a high-precision base current input for integration calculations using fused current data, and the dynamic integration coefficients adapt to the differences in battery characteristics under different SOC states. These two factors work together to reduce the inherent errors of the ampere-hour integration method, ensuring that the preliminary SOC estimate accurately reflects changes in the remaining battery capacity in real time.

[0033] Specifically, the working process of this embodiment is as follows: The data processing module is invoked to obtain the preset SOC calculation time period (e.g., 1s). The obtained fused current data (unit: A) is integrated within this time period. Specifically, it is calculated using the formula "cumulative energy value (Ah) = ∫ fused current data (A) × dt" (dt is the time period, unit: h). For example, if the fused current data is 10A and the time period is 1s (i.e., 1 / 3600h), then the cumulative energy value = 10 × (1 / 3600) ≈ 0.00278Ah, and finally the cumulative energy value reflecting the change in battery power within this time period is obtained.

[0034] The preset integral coefficient mapping table (the "calibration start SOC value - integral coefficient" correspondence table, which contains multiple sets of "calibration start SOC value - integral coefficient" data, such as integral coefficient = 1.0 when calibration start SOC value = 50% and integral coefficient = 0.95 when calibration start SOC value = 80%) is called. The calibration start SOC value obtained in step S2 is substituted into the mapping table for matching. If the calibration start SOC value exactly corresponds to a certain data in the table, the corresponding integral coefficient is read directly. If it is between two adjacent calibration start SOC values, the integral coefficient can be determined by linear interpolation (same as the interpolation logic of the OCV-SOC mapping table) to finally obtain the integral coefficient that is adapted to the current battery SOC state.

[0035] The obtained cumulative energy value is multiplied by the obtained integral coefficient, and the weighted energy value (Ah) is calculated using the formula "Weighted Energy Value (Ah) = Cumulative Energy Value (Ah) × Integral Coefficient". For example, if the cumulative energy value = 0.00278Ah and the integral coefficient = 1.0, then the weighted energy value = 0.00278 × 1.0 = 0.00278Ah. This step corrects the cumulative energy value by weighting it using the integral coefficient, eliminating the deviation in energy calculation under different SOC states.

[0036] The obtained initial SOC value is used as the initial SOC value (unit: 0.1%). Combined with the battery's rated capacity (unit: Ah), the weighted energy value is first converted into the SOC change (formula: SOC change = (weighted energy value / rated capacity) × 1000, unit: 0.1%). Then, the initial SOC estimate is calculated using the formula "Initial SOC estimate (0.1%) = Initial SOC value (0.1%) ± SOC change (0.1%)" ("+" for charging state, "-" for discharging state). For example, if the initial SOC value = 500 (i.e., 50%), the SOC change = 10 (i.e., 1%), and the battery is in a charging state, then the initial SOC estimate = 500 + 10 = 510 (i.e., 51%). Finally, the initial SOC estimate is obtained.

[0037] As an example of the above scheme, the step of collecting the voltage data of the energy storage battery, performing temperature compensation and current compensation on the voltage data to obtain the compensated voltage includes the following sub-steps: The temperature data of the energy storage battery is collected, and the voltage data is temperature compensated according to the temperature compensation coefficient to obtain the temperature compensated voltage. The fusion current data is collected, and the temperature compensation voltage is compensated for based on the current compensation coefficient to obtain the compensation voltage.

[0038] In this embodiment, battery temperature data is first collected and a temperature compensation coefficient is matched to correct the inherent differences in voltage characteristics at different temperatures. Then, based on the fused current data, a current compensation coefficient is matched to eliminate the instantaneous deviation caused by current after temperature compensation. Finally, a compensated voltage that truly reflects the battery's state of charge is output. Therefore, this embodiment effectively counteracts the dual interference of temperature and current on the voltage signal through dual compensation, making the compensated voltage closer to the battery's true open-circuit voltage characteristics at the current SOC. This provides a high-precision voltage reference for subsequently obtaining a reference SOC value based on voltage and correcting the preliminary estimation results, effectively improving the overall accuracy of SOC estimation.

[0039] Specifically, the working process of this embodiment is as follows: The temperature acquisition module of the energy storage battery (such as an NTC temperature sensor) is activated to collect the temperature data (unit: °C) of the battery cells or modules in real time and transmit it to the data processing unit; a preset "temperature-temperature compensation coefficient" mapping table is called (containing compensation coefficients corresponding to different temperatures, such as compensation coefficient Kt1 for -20℃, compensation coefficient Kt0 for 25℃, compensation coefficient Kt2 for 50℃, etc., where 25℃ is the standard temperature point and the compensation coefficient is 0), and the corresponding temperature compensation coefficient is obtained by querying the real-time temperature; the original voltage data is corrected by the formula "temperature compensation voltage = original voltage data + (real-time temperature - standard temperature) × temperature compensation coefficient" (if the real-time temperature is lower than the standard temperature, the compensation coefficient is positive to increase the voltage; if it is higher than the standard temperature, the compensation coefficient is negative to decrease the voltage), and the temperature compensation voltage that eliminates the influence of temperature is obtained. The system acquires the fused current data (unit: A) and determines whether the battery is in a charging or discharging state. It then calls a preset "current value - current compensation coefficient" mapping table (containing compensation coefficients corresponding to different current magnitudes and charging / discharging states, e.g., a 10A discharge current corresponds to compensation coefficient Kc1, and a 10A charging current corresponds to compensation coefficient Kc2). Based on the fused current data and charging / discharging state, the system retrieves the corresponding current compensation coefficient. Finally, it corrects the voltage using the formula "compensation voltage = temperature compensation voltage + (+ during discharging, - during charging) × current compensation coefficient" (during discharging, the current causes a voltage drop, requiring an added compensation coefficient; during charging, the current causes a voltage rise, requiring a subtracted compensation coefficient). This process ultimately yields a compensation voltage that simultaneously eliminates temperature and current interference.

[0040] See Figure 5The embodiment shows a schematic diagram illustrating the variation of standby open-circuit voltage OCV with SOC and temperature; ΔT is typically set to a fixed calculation period by the MCU timer, such as 100ms. Ki is the integral adjustment coefficient, and the specific calculation is as follows: 1. Based on the standby open-circuit voltage (OCV) curve table provided by the cell manufacturer, during standby, based on the battery's OCV voltage, ... Figure 4 Obtain the SOC value corresponding to the current standby open-circuit voltage OCV, and denot it as SOC-OCV; 2. In the charging state: Ki = SOC - OCV / SOC0; In the discharging state: Ki = SOC0 / SOC - OCV.

[0041] Household energy storage batteries typically rely on natural heat dissipation. Therefore, due to factors such as low ambient temperatures, the batteries cannot be completely discharged. When the battery reaches undervoltage protection, a sudden change in State of Charge (SOC) occurs. For example, at -10°C, the battery can only discharge 80% of its initial capacity, causing the SOC to jump directly from 20% to 0. This invention uses standby OCV and the single-cell voltage at the end of charge / discharge (fully considering the influence of operating current on single-cell voltage) to calibrate and correct the SOC. Based on the OCV voltage, the integral coefficient is adjusted when calculating the SOC during normal operation to improve the accuracy of SOC calculation and ensure smooth SOC changes, thereby reflecting the actual usable battery capacity.

[0042] As an example of the above scheme, the step of obtaining a reference SOC value based on the compensation voltage, comparing the reference SOC value with the preliminary SOC estimate to determine the correction direction and correction amount, and correcting the preliminary SOC estimate to obtain the SOC value to be calibrated includes the following sub-steps: The compensation voltage is linearly interpolated with the SOC mapping table to obtain the reference SOC value. The difference between the reference SOC value and the preliminary SOC estimate is calculated to obtain the SOC difference. The correction direction and correction amount are determined based on the SOC difference. The correction amount is added to the initial SOC estimate to obtain the SOC value to be calibrated.

[0043] In this embodiment, the high-precision compensated voltage after temperature and current compensation is first converted into a reference SOC value through a SOC mapping table and linear interpolation, serving as a voltage benchmark reflecting the current state of the battery. Then, the deviation is identified by calculating the difference between this value and the initial SOC estimate, thereby determining the correction direction and amount. Finally, the initial estimate is dynamically corrected to obtain the SOC value to be calibrated. Therefore, the reference SOC value in this embodiment, based on the compensated voltage signal, can accurately reflect the voltage characteristics of the battery's state of charge. The difference correction effectively offsets the accumulated error of the ampere-hour integration, enabling the SOC value to be calibrated to combine the real-time performance of the integration method with the stability of the voltage method.

[0044] Specifically, the working process of this embodiment is as follows: The system calls the preset "compensation voltage-SOC mapping table" (which is consistent with the principle of the OCV-SOC mapping table mentioned earlier, and contains multiple sets of "compensation voltage value-reference SOC value" corresponding data, such as compensation voltage = 3.2V corresponding to SOC = 40%, compensation voltage = 3.5V corresponding to SOC = 70%). If the compensation voltage happens to match a certain voltage value in the table, the corresponding reference SOC value is directly obtained; if the compensation voltage is between two adjacent voltage values ​​(let's call them V1 and V2, corresponding to SOCs SOC_ref1 and SOC_ref2, and V1 < compensation voltage < ...). Between V1 and V2, the SOC_ref is calculated using the linear interpolation formula "SOC_ref=SOC_ref1+(compensation voltage-V1)×(SOC_ref2-SOC_ref1) / (V2-V1)". For example, if the compensation voltage is 3.3V, V1=3.2V (SOC_ref1=40%), and V2=3.5V (SOC_ref2=70%), then SOC_ref=40%+(3.3-3.2)×(70%-40%) / (3.5-3.2)=50%, and the final reference SOC value is obtained.

[0045] The data processing unit calculates the difference between the reference SOC value (SOC_ref) and the preliminary SOC estimate (SOC_init). The formula is "SOC difference = SOC_ref - SOC_init". If the result is positive, it means that the preliminary estimate is lower than the reference value; if it is negative, it means that the preliminary estimate is higher than the reference value. This quantifies the degree of deviation between the two.

[0046] The correction direction is determined by the sign of the SOC difference (positive values ​​should be corrected upwards, and negative values ​​should be corrected downwards); at the same time, a preset correction strategy (such as proportional correction or segmented correction) is invoked. For example, a correction coefficient K is set (0 < K ≤ 1, such as K = 0.2), then the correction amount = SOC difference × K, to avoid SOC jumps due to excessive single correction. If the SOC difference = 5% and K = 0.2, then the correction amount = 1%, ensuring a smooth and stable correction process.

[0047] The correction amount is added to the initial SOC estimate. The formula is "SOC value to be calibrated = SOC_init + correction amount" (the sign of the correction amount is determined by the correction direction, upward correction is positive, and downward correction is negative). For example, if SOC_init = 49% and correction amount = 1%, then the SOC value to be calibrated = 50%. The final output is the SOC value to be calibrated after voltage feedback correction.

[0048] As an example of the above scheme, if the single-cell voltage of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate, including the following sub-steps: Determine whether the individual cell voltage is within the set voltage range at the end of charging or the set voltage range at the end of discharging to obtain the final judgment result; When the final judgment result is yes, the final correction amount is calculated based on the linear relationship between the unit voltage and the SOC. The end correction is added to the SOC value to be calibrated to obtain the final SOC estimate; If the final determination result is negative, the SOC value to be calibrated will be directly used as the final SOC estimate.

[0049] In this embodiment, the battery is first identified as being in a state-of-the-art (SOC) sensitive phase by determining whether the individual cell voltage has entered a preset end-of-charge / discharge range. If it is in the end-of-charge range, a correction is calculated using the strong linear relationship between voltage and SOC at that stage, accurately calibrating the SOC value to be calibrated. If it is not in the end-of-charge range, the value to be calibrated is directly used, balancing estimation efficiency and accuracy. Therefore, this embodiment effectively eliminates SOC estimation errors caused by drastic voltage changes through targeted calibration at the end of the charge / discharge cycle, avoiding the problem of SOC jumps at the end of traditional methods. This ensures that the final SOC estimate accurately reflects the actual state of the battery under all operating conditions, especially improving the estimation reliability under extreme charge states.

[0050] Specifically, the working process of this embodiment is as follows: The single-cell voltage acquisition module is activated to acquire the single-cell voltage data of the energy storage battery in real time, and the preset charging and discharging end voltage range parameters are called (e.g., the charging end voltage range is set to 4.15V~4.25V, and the discharging end voltage range is set to 2.6V~2.8V, the specific values ​​are set according to the characteristics of the battery type (e.g., lithium battery)); the real-time single-cell voltage is compared with the two sets of ranges respectively. If the voltage falls into either set of ranges, the end-of-life judgment result is "yes" (at the end of charging and discharging), otherwise it is "no" (not at the end of the life cycle).

[0051] When the final judgment result is "yes", the "Single Cell Voltage-SOC Linear Relationship Table" corresponding to the end of the charge and discharge is called (e.g., 2.6V at the end of discharge corresponds to SOC=0%, 2.8V corresponds to SOC=10%, showing a linear change); let the real-time single cell voltage be V, the lower limit of the reference voltage in this range be V_min (corresponding to SOC_min), and the upper limit be V_max (corresponding to SOC_max). It is calculated by the formula "End Correction Amount = ((V-V_current_ref) / (V_max-V_min))×(SOC_max-SOC_min)", where V_current_ref is the theoretical voltage corresponding to the SOC value to be calibrated. For example, if the SOC value to be calibrated is 5%, the theoretical voltage is 2.7V, and the actual single cell voltage is 2.65V, then the end correction amount = ((2.65-2.7) / (2.8-2.6))×(10%-0%) = -2.5%, that is, it needs to be corrected downward by 2.5%.

[0052] The end correction is added to the SOC value to be calibrated. The formula is "final SOC estimate = SOC value to be calibrated + end correction". For example, if the SOC value to be calibrated is 5% and the end correction is -2.5%, then the final SOC estimate is 2.5%, ensuring that the end SOC value is accurately matched with the actual voltage characteristics.

[0053] When the final judgment result is "no", the SOC value to be calibrated obtained above is directly used as the final SOC estimate without additional correction, so as to maintain the estimation efficiency and stability of the non-sensitive range.

[0054] See Figure 2 This is a schematic diagram of a SOC estimation system for an energy storage battery according to an embodiment of the present invention. The SOC estimation system for the energy storage battery includes: The low-power current acquisition circuit 10 is used to acquire the low-power current of the energy storage battery 14. Operating current sampling circuit 11 is used to collect the operating current of the energy storage battery 14; and, Processor 12, connected to both the low-power current acquisition circuit 10 and the operating current sampling circuit 11, is used for: The operating current and the low-power current are acquired, and the two currents are smoothly switched to obtain fused current data. Under the condition that the resting time exceeds a set threshold, the standby open circuit voltage of the energy storage battery 14 is obtained, and the SOC is calibrated once according to the standby open circuit voltage to obtain the calibration start SOC value. Based on the fused current data and the integral coefficient corresponding to the calibration initial SOC value, an ampere-hour integral calculation is performed to obtain a preliminary SOC estimate. The voltage data of the energy storage battery 14 is collected, and temperature compensation and current compensation are performed on the voltage data to obtain the compensation voltage; A reference SOC value is obtained based on the compensation voltage. The reference SOC value is compared with the preliminary SOC estimate to determine the correction direction and correction amount. The preliminary SOC estimate is then corrected to obtain the SOC value to be calibrated. If the voltage of a single cell of the energy storage battery 14 enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate.

[0055] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: By employing a dual-channel sampling system ("operating current sampling circuit + low-power current sampling circuit") with smooth switching, a wide-range, high-precision fused current data is first obtained. Only when the resting time exceeds a set threshold is the standby open-circuit voltage used for a one-time calibration to obtain the initial SOC value. Subsequently, the fused current data is integrated with the integral coefficient corresponding to this initial SOC value to obtain a preliminary SOC estimate. Then, the SOC value is obtained by querying the SOC mapping table using the compensation voltage after temperature and current compensation. After comparing it with the preliminary SOC estimate, the correction direction and amount are determined and corrected to obtain the SOC value to be calibrated. Finally, when the individual cell voltage enters the set voltage range at the end of the charge / discharge period, end calibration is performed based on the voltage characteristics. Otherwise, the SOC value to be calibrated is directly output as the final SOC estimate. This approach improves the accuracy of low current through dual-channel sampling, eliminates accumulated errors through one-time calibration with standby OCV, and suppresses SOC jumps through real-time compensation and end calibration. As can be seen from the above analysis, the embodiments of the present invention effectively solve the problems of low power consumption, inaccurate current sampling, and SOC jump during battery undervoltage protection in the prior art caused by only single-loop current sampling. It realizes accurate estimation of SOC of energy storage battery and ensures smooth SOC change, accurately reflects the actual usable power of battery, and thus effectively improves the accuracy of SOC estimation.

[0056] As an example of the above scheme, when the processor is used to acquire the working current and low-power current of the energy storage battery through the working current sampling circuit and the low-power current sampling circuit respectively, and to perform smooth switching processing on the two currents to obtain fused current data, it is specifically used for: The operating current of the energy storage battery is collected by the operating current sampling circuit to obtain the operating current data; The low-power current of the energy storage battery is collected by a low-power current sampling circuit to obtain low-power current data. The amplitude of the operating current data is compared with that of the low power consumption current data to obtain the amplitude comparison result; Based on the amplitude comparison results, the operating current data and the low-power current data are subjected to a weighted smoothing switching operation according to the set switching threshold range to obtain the fused current data.

[0057] As an example of the above scheme, when the processor is used to obtain the standby open-circuit voltage of the energy storage battery under the condition that the resting time exceeds a set threshold, and to perform a calibration of the SOC based on the standby open-circuit voltage to obtain the calibration starting SOC value, specifically it is used to: The set threshold is determined by the RTC time difference, and the result of the settling time determination is obtained. When the static judgment result is yes, the average voltage of the energy storage battery is collected as the standby open circuit voltage; The standby open-circuit voltage is linearly interpolated with the SOC mapping table to obtain the calibration starting SOC value.

[0058] It is understood that the embodiments of the above-mentioned SOC estimation system for energy storage batteries can be referred to the relevant embodiments of the above-mentioned SOC estimation method for energy storage batteries, and will not be elaborated here.

[0059] It should be noted that the system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the system embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0060] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for estimating the State of Charge (SOC) of an energy storage battery, characterized in that, include: The working current and low-power current of the energy storage battery are collected by the working current sampling circuit and the low-power current sampling circuit respectively, and the two currents are smoothly switched to obtain fused current data. Under the condition that the resting time exceeds a set threshold, the standby open-circuit voltage of the energy storage battery is obtained, and the SOC is calibrated once based on the standby open-circuit voltage to obtain the calibration start SOC value. Based on the fused current data and the integral coefficient corresponding to the calibration initial SOC value, an ampere-hour integral calculation is performed to obtain a preliminary SOC estimate. Start the temperature acquisition module of the energy storage battery to collect the temperature data of the individual energy storage battery cells or modules in real time; The voltage acquisition module of the energy storage battery is activated to acquire the individual cell voltage data of the energy storage battery in real time. The voltage data of the energy storage battery is collected, and temperature compensation and current compensation are performed on the voltage data to obtain the compensation voltage; A reference SOC value is obtained based on the compensation voltage. The reference SOC value is compared with the preliminary SOC estimate to determine the correction direction and correction amount. The preliminary SOC estimate is then corrected to obtain the SOC value to be calibrated. If the voltage of a single cell of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate.

2. The SOC estimation method for energy storage batteries as described in claim 1, characterized in that, The process of acquiring the operating current and low-power current of the energy storage battery through a working current sampling circuit and a low-power current sampling circuit respectively, and then smoothly switching the two currents to obtain fused current data includes the following sub-steps: The operating current of the energy storage battery is collected by the operating current sampling circuit to obtain the operating current data; The low-power current of the energy storage battery is collected by a low-power current sampling circuit to obtain low-power current data. The amplitude of the operating current data is compared with that of the low power consumption current data to obtain the amplitude comparison result; Based on the amplitude comparison results, the operating current data and the low-power current data are subjected to a weighted smoothing switching operation according to the set switching threshold range to obtain the fused current data.

3. The SOC estimation method for energy storage batteries as described in claim 1, characterized in that, The step of obtaining the standby open-circuit voltage of the energy storage battery under the condition that the resting time exceeds a set threshold, and calibrating the SOC based on the standby open-circuit voltage to obtain the calibration starting SOC value, includes the following sub-steps: The set threshold is determined by the RTC time difference, and the result of the settling time determination is obtained. When the static judgment result is yes, the average voltage of the energy storage battery is collected as the standby open circuit voltage; The standby open-circuit voltage is linearly interpolated with the SOC mapping table to obtain the calibration starting SOC value.

4. The SOC estimation method for energy storage batteries as described in claim 1, characterized in that, The step of performing ampere-hour integration calculation based on the fused current data and the integration coefficient corresponding to the calibration initial SOC value to obtain a preliminary SOC estimate includes the following sub-steps: The cumulative energy value is obtained by integrating the fused current data over the time period; The integral coefficients are obtained by querying the integral coefficient mapping table based on the initial SOC value of the calibration. Multiply the cumulative power consumption value by the integral coefficient to obtain the weighted power consumption value; Add the initial SOC value to the weighted energy value to obtain a preliminary SOC estimate.

5. The SOC estimation method for energy storage batteries as described in claim 1, characterized in that, The process of collecting voltage data from the energy storage battery and performing temperature and current compensation on the voltage data to obtain a compensated voltage includes the following sub-steps: The temperature data of the energy storage battery is collected, and the voltage data is temperature compensated according to the temperature compensation coefficient to obtain the temperature compensated voltage. The fusion current data is collected, and the temperature compensation voltage is compensated for based on the current compensation coefficient to obtain the compensation voltage.

6. The SOC estimation method for energy storage batteries as described in claim 1, characterized in that, The process of obtaining a reference SOC value based on the compensation voltage, comparing the reference SOC value with the preliminary SOC estimate to determine the correction direction and amount, and correcting the preliminary SOC estimate to obtain the SOC value to be calibrated includes the following sub-steps: The compensation voltage is linearly interpolated with the SOC mapping table to obtain the reference SOC value. The difference between the reference SOC value and the preliminary SOC estimate is calculated to obtain the SOC difference. The correction direction and correction amount are determined based on the SOC difference. The correction amount is added to the initial SOC estimate to obtain the SOC value to be calibrated.

7. The SOC estimation method for energy storage batteries as described in claim 1, characterized in that, If the voltage of a single cell in the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate. This includes the following sub-steps: Determine whether the individual cell voltage is within the set voltage range at the end of charging or the set voltage range at the end of discharging to obtain the final judgment result; When the final judgment result is yes, the final correction amount is calculated based on the linear relationship between the unit voltage and the SOC. The end correction is added to the SOC value to be calibrated to obtain the final SOC estimate; If the final determination result is negative, the SOC value to be calibrated will be directly used as the final SOC estimate.

8. A SOC estimation system for an energy storage battery, characterized in that, include: Low-power current acquisition circuit, used to acquire the low-power current of energy storage battery; Operating current sampling circuit, used to collect the operating current of the energy storage battery; and, The processor, connected to both the low-power current acquisition circuit and the operating current sampling circuit, is used for: The operating current and the low-power current are acquired, and the two currents are smoothly switched to obtain fused current data. Under the condition that the resting time exceeds a set threshold, the standby open-circuit voltage of the energy storage battery is obtained, and the SOC is calibrated once based on the standby open-circuit voltage to obtain the calibration start SOC value. Based on the fused current data and the integral coefficient corresponding to the calibration initial SOC value, an ampere-hour integral calculation is performed to obtain a preliminary SOC estimate. Start the temperature acquisition module of the energy storage battery to collect the temperature data of the individual energy storage battery cells or modules in real time; The voltage acquisition module of the energy storage battery is activated to acquire the individual cell voltage data of the energy storage battery in real time. The voltage data of the energy storage battery is collected, and temperature compensation and current compensation are performed on the voltage data to obtain the compensation voltage; A reference SOC value is obtained based on the compensation voltage. The reference SOC value is compared with the preliminary SOC estimate to determine the correction direction and correction amount. The preliminary SOC estimate is then corrected to obtain the SOC value to be calibrated. If the voltage of a single cell of the energy storage battery enters the set voltage range at the end of the charge / discharge period, the SOC value to be calibrated is calibrated at the end based on the voltage characteristics to obtain the final SOC estimate; otherwise, the SOC value to be calibrated is directly used as the final SOC estimate.

9. The SOC estimation system for energy storage batteries as described in claim 8, characterized in that, The processor is used to acquire the operating current and low-power current of the energy storage battery through the operating current sampling circuit and the low-power current sampling circuit respectively, and to perform smooth switching processing on the two currents to obtain fused current data. Specifically, it is used for: The operating current of the energy storage battery is collected by the operating current sampling circuit to obtain the operating current data; The low-power current of the energy storage battery is collected by a low-power current sampling circuit to obtain low-power current data. The amplitude of the operating current data is compared with that of the low power consumption current data to obtain the amplitude comparison result; Based on the amplitude comparison results, the operating current data and the low-power current data are subjected to a weighted smoothing switching operation according to the set switching threshold range to obtain the fused current data.

10. The SOC estimation system for energy storage batteries as described in claim 8, characterized in that, The processor is used to acquire the standby open-circuit voltage of the energy storage battery when the resting time exceeds a set threshold, and to perform a calibration of the SOC based on the standby open-circuit voltage to obtain the calibration starting SOC value. Specifically, it is used for: The set threshold is determined by the RTC time difference, and the result of the settling time determination is obtained. When the static judgment result is yes, the average voltage of the energy storage battery is collected as the standby open circuit voltage; The standby open-circuit voltage is linearly interpolated with the SOC mapping table to obtain the calibration starting SOC value.

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